1. Field of the Invention
The present invention relates to a process for producing a resin-sealed type electronic device which comprises forming a dam frame on a substrate loaded with at least one electronic element so as to encompass the electronic element, pouring a resin for sealing in the inside of the dam frame, and heat-curing the poured resin.
2. Description of the Related Arts.
In general, semiconductor chips and integrated circuits (IC), etc. that are constituted of internally contained semiconductor chips are employed as a resin-sealed electronic devices.
For the resin sealing, there is prevalently used a method which comprises housing a substrate loaded with an electronic element in a cavity of a die, and transfer injection molding a resin for sealing. However, the above-mentioned method involves such problems as requiring much expense for equipment such as dies, and in particular being difficult to cope with small lots and multi-item manufacture.
Conversely as a method easy to cope with small lots and multi-item manufacture, there is carried out a method which comprises forming a dam frame on a substrate loaded with at least one electronic element so as to encompass the electronic element, pouring a low viscosity resin for sealing in the inside of the dam frame, and heat-curing the poured resin.
The dam frame in the method is intended to prevent the resin for sealing from leaking out therefrom, and is usually formed by coating prescribed portions with a leakage preventive material composed of a high viscosity resin for sealing and/or a sealant, and heat-curing the material {for instance, refer to Patent Literature 1: Japanese Patent Application Laid-Open No. 124401/2003 (Heisei 15)}.
However the method just mentioned involves the problem of intricate steps of applying a leakage preventive material and heat-curing the same, increased number of steps, requiring a long time for heat-curing, and also requiring a long time up to the formation of the dam frame, and in turn for the entire steps.